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New member and new poster here! I’ve been a flashlight fan for a few years but only a lurker until now.

I recently purchased a Convoy S2+ on Gearbest with an XM L2 T6 – 4C emitter and “3 / 5 Modes”. Upon first power on with a brand new and fully charged protected NCR18650GA (protected and wrapped by EVVA, purchased on mtnelectronics), all I get is blinking at approximately 1Hz (see video Dropbox Link

I’ve tried everything – half clicks rapidly many many times, switching on and off and so on and so forth. Nothing results in a steady beam – only blinking! At one point it did begin flashing at a faster rate (maybe 2-3 times faster).

Have you tested the new battery in another torch to see if it’s halal? If it’s alright, then it could be a faulty driver. If you could remove the pill and take some shots of it, we should be able to diagnose the issue much faster.

(Quick question: did you pick 3/5 on purpose or was it because it’s all you had available? Because if it’s the latter, sounds like a driver swap is in order. Biscotti is just the tip of the iceberg, and it’s pretty amazing itself )

Jack, thanks for the response! I’ll have to find some needle nose pliers tomorrow and pull the pill. I chose 3/5 because that’s all that was available… Believe it or not, this is my only 18650 torch. I’ve used the battery in a Nitecore F2 charger/powerbank and it charges my phone just fine, but that’s about all I can say.

If I were to swap the driver, where would be the best place to pick one up?

Remove the tail cap and use a piece of wire or something to touch the end of the battery to the raw aluminum edge of the tube. See if you get a steady beam then. Buddy of mine brought over a S2+ a few weeks ago and his tail switch took a dump on him. Replaced it and the problem went away. Might check and see if the retaining ring on both the driver and the tail cap switch is tight as well.

That’s the low voltage warning. The cause of that if the battery is full would be high electrical resistance (poor contact) somewhere.

In addition to the retainer ring, check that the battery tube is not backwards. The “S2+” text should be towards the tail. It will physically fit if put backwards but contact will be rather poor. It’s also possible that the tail switch is defective.

Remove the tail cap and use a piece of wire or something to touch the end of the battery to the raw aluminum edge of the tube. See if you get a steady beam then. Buddy of mine brought over a S2+ a few weeks ago and his tail switch took a dump on him. Replaced it and the problem went away. Might check and see if the retaining ring on both the driver and the tail cap switch is tight as well.

This suggestion is definitely a first step in finding the cause. It helps to pinpoint the trouble to the head-section or to the tail-section. FWIW, this light occasionally has troubles if the switchboard is a fraction to large, it does not properly “sink in” the retaining ring of the tailcap assembly. Giving the retaining ring an extra nudge might help.

Please elaborate on the properties of the light. Is it a light with a rubber tailcap or a metal tailcap. Also specify the capacity of the driver. If it is an AMC7135*6 or AMC7135*8 driver, it is soldered to the pill. So no need for tightening a retaining ring on that end. Because there is none.

Remove the tail cap and use a piece of wire or something to touch the end of the battery to the raw aluminum edge of the tube. See if you get a steady beam then. Buddy of mine brought over a S2+ a few weeks ago and his tail switch took a dump on him. Replaced it and the problem went away. Might check and see if the retaining ring on both the driver and the tail cap switch is tight as well.

This suggestion is definitely a first step in finding the cause. It helps to pinpoint the trouble to the head-section or to the tail-section. FWIW, this light occasionally has troubles if the switchboard is a fraction to large, it does not properly “sink in” the retaining ring of the tailcap assembly. Giving the retaining ring an extra nudge might help.

Please elaborate on the properties of the light. Is it a light with a rubber tailcap or a metal tailcap. Also specify the capacity of the driver. If it is an AMC7135*6 or AMC7135*8 driver, it is soldered to the pill. So no need for tightening a retaining ring on that end. Because there is none.

Henk4U2, it has a metal tail cap and switch, not the rubber/silicone covered one. It has 8× 7135 chips. I’ll check the tail cap retaining ring per toddcshoe’s suggestion tonight, as well as jumpering the battery’s end directly to the body of the flashlight. The tail cap switch itself seems to function fine, at least based on feel, which probably isn’t saying much, but we’ll see.

Unscrew the head. You’ll see the pill in there, use the needlenose pliers to screw it off. I’m guessing the driver is soldered to the pill instead of held with a retaining ring – if it is you’ll have to de-solder it with an iron, otherwise use the pliers to unscrew the retaining ring.

The only thing visually apparent is that the LED board separated from the pill slightly. There’s thermal transfer compound between the LED board and the pill surface, but they weren’t touching. The board is just floating a little above the pill. Is that an issue? I assume not as it must compress together once it’s pressed against the reflector in the body.

Is it worth de-soldering everything at this point and re-soldering the four connection points? I’ll be honest – I have very little soldering experience and my iron is a piece of junk. Perhaps it’s time to invest in a new one.

They’ve already refunded my money – I was just wondering if it’s worth trying to resurrect.

It is if you get a driver from Simon at Convoy’s Ali store. You can purchase Biscotti drivers at whatever number of 7135s you want at a very good price. The S2+‘s host is practically a legend, and worth experimenting with.

Also yeah, it’s a good idea to get a better iron. My brother and I struggled quite a bit with a weak one that didn’t even melt the solder right, so I went ahead and got a decent 60w one in my following trip to the hardware store. All is good in the neighborhood for future driver or emitter swaps.

Beautiful. I got that exact driver to replace the 3/5 I had on my first S2 – I have another one with 7135×6 Biscotti but this one has sentimental value (and the LED tint is rosier and nicer) –, and since I did the swap I’ve been enjoying it a lot. It’s been my go-to biking light in these final days of Daylight Savings Time when it’s complete darkness before 6AM (I leave the house between 5:30 and 5:45AM, when there’s barely a hint of dawn in the sky).

Just be careful not to run it pell mell at 100% power too long, the S2+ doesn’t have the cooling potential to safely maintain that much output. I like to keep my S2 at mode group 8 (max mode 50% of full power) and will do the same when my Nichia S2+ gets to me.

Yeah, I’ll probably leave it on mode 8 as well. How do you find the 7145 ×6? Are you able to leave it at 100% for any longer?

When on 50% power with the 7135 ×8 can you run it continuously?

Cheers!

It depends. I had a 7145 ×6 turn on in my jacket by accident and it was too hot to hold after it was on for guessing 5 to 10 minutes. I had to hold it with my jacket sleeve just to be able to turn it to off. But holding it in my hand on other occasions, it was hot but bearable to hold.

Yeah, I’ll probably leave it on mode 8 as well. How do you find the 7145 ×6? Are you able to leave it at 100% for any longer?

When on 50% power with the 7135 ×8 can you run it continuously?

Cheers!

I’d gone for it for heating reasons, but once I found a temperature test that indicated an S2+ in x6 reaching the same risky max temperature as x8 but a bit slower, I decided “bugger it” and went for x8 when I got the new drivers. I did notice the x8 being marginally brighter than the x6 on 10% mode and above.

On 50% it’s like you’re running a 7135×4 at full blast, which is very much tried and safe. During my 15-ish minute morning commute, it doesn’t even get warm. And the battery lasts forever. Not bad at all for swapping about 25% perceived brightness for more or less 2 more hours of runtime

most things with LVP faults come from a defect on the voltage divider,
the S2+ should have 19.1k and 4.7k to generate about 0.7V on MCU pin 7 which gets compared to a internal voltage reference
it happens that one resistor end is not correctly reflow soldered and does not give electrical contact, as the LVP ready low this has to be on the 19.1k resistor

Nice. I’m looking forward to a high quality 4000 kelvin light. The SST-20 also looks to be efficient, with a higher lumen output than the 219C, I think.

I have a Samsung LH351D 5000K 90cri I believe. A friend bought a bunch and sent a few my way. I can send you one on a 16mm Mountain board if you would like to try it out. No charge or anything. I don’t have any 4000K emitters but I don’t mind flowing a emitter on a board for you if it would make your light more enjoyable. Just PM an address and I can get it in the mail sometime tomorrow.

I put that emitter in a few of my Jetbeam Jet-I MK and they are quite pleasant.

Lexel, my technical expertise is wood science (it’s true! Lol), so, I immensely appreciate your response, but have no idea what it means.

go to your garage
take a soldering iron, with a small tip
stick it to the tiny part with 28C or 223 marking on both sides and see if that fixes the problem
holding the resistor with tweezers is helpful if you hit the good side it becomes loose if other is not soldered right

Lexel, my technical expertise is wood science (it’s true! Lol), so, I immensely appreciate your response, but have no idea what it means.

go to your garage
take a soldering iron, with a small tip
stick it to the tiny part with 28C or 223 marking on both sides and see if that fixes the problem
holding the resistor with tweezers is helpful if you hit the good side it becomes loose if other is not soldered right